Lighting system with removable light modules

ABSTRACT

A lighting system with removable light modules mounted on a frame by an attractive force between magnetic material of the light module and magnetic material of the frame such that a light module may be installed on, removed from, or relocated on the frame manually without tools or permanent electrical connection. The frame may be one-, two-, or three-dimensional, and it may provide an aesthetic appearance even when the lighting system is not illuminated. The light modules may employ incandescent, quartz-halogen, LED, or fluorescent light sources. Particularly, in LED embodiments, the magnetic materials serve the dual functions of mounting and heat sinking. The lighting system may be utilized as a sign, signaling device, or a building block in larger lighting systems. The lighting system has a wide variety of applications and provides a user with improved ability to control the quantity, direction, and characteristics of the emitted light.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to lighting systems and more particularly tolighting systems having manually insertable and removable light modulessuch that the quantity, direction, and/or characteristics of the lightemitted from the system may readily be varied.

2. Background Art

In modern lighting systems, it is desirable to have a great deal offlexibility in the user's ability to control the quantity, direction,and characteristics of the light emitted from the system. In theatersettings, one is accustomed to observing a number of light fixturescapable of directing light of varying intensities, color, and othercharacteristics onto the stage. In commercial settings, adjustablereflector lamps and track lights are frequently employed to illuminatemerchandise or displays. In office and residential settings, tracklights are typically used to direct light to a particular work area orfor visual effect. While these systems are flexible, they havedisadvantages. One disadvantage is that they are relatively large in thesense that the light fixtures are conspicuous. In many applications,such as in a display case for jewelry or other fine wares, it isdesirable for the lighting system to be as inconspicuous as possible. Inapplications where the appearance of the lighting system itselfcontributes to its overall aesthetics, there are additional design andproduction costs. Another disadvantage is that while these systems areflexible, they may be cumbersome to adjust for different lightingrequirements. In many cases, the light fixtures are relatively heavy. Tomove, add, or remove a light fixture with a mechanical connector, a toolmay be required and, in some cases, a new electrical connection may berequired. Even where the light fixture may be rotatably mounted, thebase of the light fixture typically is moveable only in a singledimension. Lastly, there is the disadvantage that these systems arerelatively costly.

U.S. Pat. No. 5,154,509, issued on Oct. 13, 1992, to Wulfman et al.,describes a low-voltage track lighting system wherein the light fixtureis mounted on the track by means of magnetic force, and electrical poweris conveyed from the track to the fixture by means of physical contactsbetween the electrical leads of the track and fixture. Wulfman et al.teaches a conventional track-lighting system, i.e., a number of lightfixtures movably mounted on a linear track. The light fixtures ofWulfman et al. are mounted on a triangular bracket. Electrical power istransmitted from the bracket to the housing of the fixture by means ofelectrical contacts located on two sides of the triangular bracket andtwo sides of the matching angular recess of the housing. The track andlight fixtures of Wulfman et al. are purely functional in design, ie.,to provide and direct light.

BRIEF SUMMARY OF THE INVENTION

It is therefore an object of the invention to obviate the deficienciesof the prior art.

Another object of the invention is to enhance lighting systems and auser's ability to control lighting systems.

Still another object of the invention is to provide a lighting systemthat can employ incandescent, quartz-halogen, LED, and fluorescent lightsources.

A further object of the invention is to provide a lighting systemcapable of being fabricated into numerous three-dimensional solidshapes, e.g., parallelepipeds, spheres, polyhedra.

These objects are accomplished, in one aspect of the invention, byprovision of a lighting system with removable light modules. The framehas a substantially flat surface and includes a magnetic material andfirst and second electrically conductive channels. The removable lightmodule includes a light source mounted on a base. The base has asubstantially flat surface and includes a magnetic material and firstand second electrically conductive paths. The light source has first andsecond lead-in wires electrically connected to the first and secondelectrically conductive paths of the base.

The light module is mounted on the frame with the substantially flatsurface of the module's base facing the substantially flat surface ofthe frame such that the light module is securely mounted on the frame bymeans of a magnetic attractive force acting between the magneticmaterial of the module and the magnetic material of the frame and suchthat the magnetic attractive force permits the light module to bemanually removed from the frame.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a pictorial view of a lighting system in accordance with anembodiment of the invention.

FIG. 2 is an enlarged cross-sectional view of the lighting system ofFIG. 1 taken along line 2-2. FIG. 2A illustrates the embodiment of theinvention shown in FIG. 2 wherein the electrically conductive frameserves as one electrical channel.

FIG. 3 is a sectional view of an alternate embodiment of the invention.

FIG. 4 is a sectional view of an alternate embodiment of a light module.

FIG. 5 is a pictorial view of a frame for a lighting system.

FIG. 6 is an elevational view of a circular frame for a lighting system.

FIG. 7A is an elevational view of a spherical frame for a lightingsystem.

FIG. 7B is an elevational view of a spherical frame for a lightingsystem with a portion of the spherical surface cut away.

FIGS. 8A and 9A are isometric views of solid frames for a lightingsystem in the shapes of an icosahedron and a dodecahedron, respectively.FIG. 8B is an elevational view of one triangular face of FIG. 8A, andFIG. 9B is an elevational view of one pentagonal face of FIG. 9A.

FIG. 10 is a cross-sectional view of an alternate embodiment of alighting system with means for aligning the light module on the frame.

FIG. 11 is a cross-sectional view of another alternate embodiment of thelighting system with means for insuring proper alignment and electricalpolarity of the light module on the frame.

FIG. 12 is a pictorial view of an embodiment of the invention mounted ina display case.

DETAILED DESCRIPTION OF THE INVENTION

For a better understanding of the present invention together with otherand further objects, advantages, and capabilities thereof, reference ismade to the following disclosure and appended claims taken inconjunction with the above-described drawings.

For purposes herein, the following definitions apply. A “removable lightmodule” means a light module that may be mounted on, removed from, orrelocated on the frame manually without use of tools or need forpermanent manipulated electrical connections, such as a connection madewith a screw, splice, wire nut, etc. The term “magnetic material” meansa material that is either a permanent magnet or a material that isstrongly attracted by a permanent magnet. A phrase stating that anarticle is mounted on a surface of an object includes an arrangementwherein the article is mounted within the object such that a surface ofthe article comprises or coincides with a portion of the surface of theobject. The term “LED” means light-emitting diode, and the term “LED”may include a current-limiting resistor electrically connected in serieswith the light-emitting diode. The term “low voltage” means abouttwenty-four volts or less; the term “high voltage” means a voltage otherthan low voltage. The term “electrical polarity” or “polarity” means thedirection in which a direct current flows, and the term “oppositepolarity” or “different polarity” means the direction opposite to thatin which a direct current flows.

Referring now to the drawings with greater particularity, it should benoted that the orientation of the invention and emitted light shown inthe drawings are by way of example and not limitation. In manyapplications, the light will be emitted substantially downward. FIG. 1shows lighting system 10 comprising a frame 12 and a removable lightmodule 14. Frame 12 may be formed entirely from a magnetic material,such as iron, or from a non-magnetic material, such as plastic, with oneor more pieces of magnetic material imbedded in it. In embodiments wherethe frame material is electrically conductive, dielectric coating 16(shown in more detail in FIG. 2) may be used to insulate electricallyconductive channels 18 and 20 from each other and from body 26 of theframe. Electrically conductive channels 18 and 20 are thin electricallyconductive strips, e.g., copper foil. Terminals 22 and 24 provide meansfor connecting lighting system 10 to an external source of electricalpower. Where the frame is electrically conductive, the frame may serveas one of the electrically conductive channels, e.g., ground,particularly in low-voltage applications.

Light module 14 has light source 28 mounted on base 30. Light source 28has lead-in wires 36 and 38 connected to electrically conductive paths32 and 34 that make physical and electrical contact with channels 20 and18, respectively, of frame 12. In various aspects of the invention,light source 28 will be replaceably mounted on the base such that thelight source, e.g, a light bulb, may be replaced at its end of life. Asdiscussed above, dielectric coating 31 (shown in more detail in FIG. 2)may be used to insulate electrically conductive paths 32 and 34 fromeach other and from base 30. Electrically conductive paths 32 and 34 areformed from thin electrically conductive material, e.g., copper foil.Base 30 may be formed entirely from a magnetic material, such as iron,or from a non-magnetic material, such as plastic, with one or morepieces of magnetic material imbedded in it. The magnetic material offrame 12 may be a permanent magnet that attracts the magnetic materialof base 30 or, conversely, the magnetic material of base 30 may be apermanent magnet that will attract the magnetic material of frame 12. Ineither case, the magnetic attraction between light module 14 and frame12 must be of sufficient strength to hold module 14 securely on frame 12while still permitting the module to be mounted on, removed from, orrelocated on frame 12 manually without use of tools or need forpermanent electrical connections. In the embodiment shown in FIG. 2A,electrically conductive frame 12 serves as one electrical channel. Ridge21 of body 26 of frame 12 is in physical and electrical contact withpath 32 (thereby obviating the need for channel 20 that is electricallyisolated from body 26 as depicted in FIG. 2).

A flex circuit including channels 18 and 20 may serve as frame 12. Theflex circuit with pressure-sensitive thermally conductive adhesive maybe applied to any magnetic substrate material without dielectrictreatment. The dielectric strength will be provided by the flex circuitmaterial. This type of frame is particularly well suited for mountingunder a sheet metal shelf or cabinet or the like or on a flex magneticstrip.

FIG. 2 is an enlarged sectional view of lighting system 10. FIG. 2illustrates the electrical circuit of lighting system 10. As seen inFIG. 1, electrical power from an external source is supplied acrosselectrically conductive channels 18 and 20. FIG. 2 shows channel 18 inelectrical contact with electrically conductive path 34, and channel 20in electrical contact with electrically conductive path 32. Paths 32 and34 connect to lead-in wires 36 and 38, respectively, of light source 28.Dielectric coating 31, e.g., an electronic grade porcelain enamel,electrically insulates paths 32 and 34 from each other and base 30. Anynumber of conventional dielectric or resistive coating materials, suchas, for example, porcelain enamel, glass, ceramic, organic electricallyinsulating materials, or glass/ceramic coatings, may be used inconnection with the present invention. A dielectric coating may not berequired with the use of magnets having high electrical resistance,e.g., ceramic magnets. However, such magnets must also have adequatethermal conductivity for their heat-sinking function as will bediscussed below. To avoid the possibility of shorting the framechannels, width w (shown in FIG. 2) between frame channels 18 and 20should be wide enough to prevent either path 32 or path 34 fromsimultaneously touching both channels even if module 14 is twisted onframe 12.

Referring now to FIG. 3, there is shown a lighting system 50 that haschannels 18 and 20 located within electrically insulated grooves 52 and54 of frame 62. Surface 60 of frame 62 may include dielectric coating 16outside grooves 52 and 54 to prevent electrical contact of paths 32 or34 with frame 62. Dielectric material 56 and 58 can be formed from anysuitable non-conductive material that may be the same as, or differentfrom, the material of dielectric coating 16. As discussed above,dielectric material 56 and 58 may not be required when paths 32 and 34are electrically isolated from each other by virtue of thenon-conductivity of the frame material surrounding grooves 52 and 54.

In the embodiments shown in FIGS. 1-3, light source 28 preferably is aLED. LED light modules are typically light, compact, and relativelyrugged and inexpensive. LED embodiments of the invention areparticularly well suited for display where the physical lighting systemsare intended to be as compact and inconspicuous as possible. The framemay be thin, e.g., a thin piece of steel, with the dielectric coatinglocated only below the electrical contacts. The light modules may have alow profile such that the overall lighting system is ideal for displayapplications. The frame may be formed in or by a surface of a structure,such as a shelf, display case top, underside of a cabinet, etc. In acase where a frame has insufficient interior volume, a portion or all ofthe electrical-support and/or control devices may be located remotely.

The optimum voltage for driving a circuit with a plurality of LED lightsources will depend on the number of light sources, theircharacteristics and arrangement in the circuit, and other circuitcomponents. The current may be direct or alternating depending on theapplication. With an LED light source, the electrical power appliedacross terminals 22 and 24 of FIGS. 1-3 is preferably about five voltsdirect current but, as will be discussed below, alternating current maybe desired in some LED applications. With tungsten-halogen lamps, suchas MR-16 lamps frequently employed in track lighting, the voltageapplied across terminals 22 and 24 is preferably about twelve volts. Ineither of these low-voltage embodiments, there is no danger ofelectrical shock resulting from exposed electrical channels 18 and 20.

However, other types of light sources, such as incandescent,tungsten-halogen, and fluorescent lamps, are within the scope of theinvention. A step-down transformer may used to reduce the voltageapplied across terminals 22 and 24 where required, e.g., traditionaltungsten-halogen track lighting. In high-voltage embodiments, thelighting system may be mounted in a housing with a light-transmissivecover preventing access to exposed channels 18 and 20, preferably with akill switch that automatically shuts off the power across channels 18and 20 when the cover is open.

Particularly in LED applications, magnetic base 30 and frame 26 aresized to function as a heat sink that conducts sufficient heat away fromlight module 28 to satisfy the module's thermal operating requirements.More particularly, the magnet serves as a thermal path for heat transferto the substrate portion of the frame. The substrate is the effectiveheat sink.

A wide variety of LEDs in all colors suitable for use in accordance withthe invention is available from Osram Opto Semiconductors Inc., 2650 SanTomas Expressway, Suite 200, Santa Clara, Calif. 95051. LEDs from theDragon® Family are particularly well suited.

Referring to FIG. 4, an alternate embodiment of a light source is shown.Light source 80 of FIG. 4 may be substituted for light source 28 of FIG.1 by electrically connecting lead-in wires 82 and 84 to channels 32 and34, respectively. Light source 80 includes cylindrical sleeve 86 havingcentral axis A-A. Reflector 88, also with central axis A-A, is mountedwithin sleeve 86. Reflector 88 may be parabolic, as shown in FIG. 4, orsome other shape in order to obtain a desired beam pattern. Reflector 88typically has light-reflective coating 89 on its inside surface. Lens 90may be removably mounted on sleeve 86 by suitable means, e.g., by thread92 such that lens 90 may be screwed into sleeve 86 in front of light LED96 or by being pushed onto two spade posts. As is well known in the art,lens 90 may be shaped, patterned, and/or coated to produce variouscharacteristics of light emitted from light source 80. Further, lens 90may be colored to match or be different from the color of the lightemitted from light source 80. Lens 90 may be opaque or semi-opaqueeverywhere except for the outline of an alphanumeric character or someother symbol such that light source 80 projects the image of suchcharacter or symbol when the light source is lit. Because lens 90 isreplaceable, the character or effect of the light emitted from lightsource 80 may be changed by replacing lens 90 with a different lens. InFIG. 4, light source 80 employs LED 96 as the light-generating device,but a different light-generating source may be employed. In an alternateembodiment of the invention (not shown in the drawings), reflector 88may be movably mounted on the light module such that the direction ofthe emitted beam may be adjusted without relocating the light module onthe frame. See, for examples, U.S. Pat. No. 5,154,509, issued on Oct.13, 1992, to Wulfman et al. (mentioned above) and U.S Pat. No.4,719,549, issued Jan. 12, 1988, to Apel.

FIG. 5 is a pictorial view of a frame 100 for use with one or more lightmodules in accordance with various aspects of the invention. Frame 100differs from frame 12 of FIG. 1 in that there is a plurality of pairs ofelectrically conductive channels on which one or more light modules maybe magnetically mounted. In the drawing, channels 102 and 104 form afirst channel pair, channels 106 and 108, a second pair, and channels110 and 12, a third pair. If desired, additional pairs of channels maybe added to frame 100. Each channel may be formed from a thinelectrically conductive material and mounted on body 101 covered with adielectric coating as shown in FIG. 2, or each channel may be mounted inan insulated groove in body 101 as shown in FIG. 3. Terminals 114 and116 may be connected to an external source of electrical power. Theelectrically conductive channels, and/or channel pairs, may befabricated by printed circuit board techniques. In an embodiment such asshown in FIG. 5, there is the advantage that a plurality of lightmodules may be mounted on the frame substantially in the form of anarray, i.e., an arrangement of rows and columns in the x- andy-directions.

Frame 100 may have a variety of embodiments and applications. In avertical orientation as depicted in FIG. 5, frame 100 may be used as afixture for signage. Light modules with alphanumeric lenses may bemounted on frame 100 so as to display a message. When mountedhorizontally with the channels facing down under a counter or in adisplay case, frame 100 accommodates a flexible arrangement of lightmodules, positionable in both x- and y-directions, to direct light ontoa particular work area or areas, or to highlight certain merchandise,perhaps with different light intensities, colors, or aesthetic effects.

FIG. 12 illustrates an embodiment of the invention mounted in displaycase 300. Display case 300 has lighting system 303 mounted on theunderside of top shelf 302. Objects 310 situated on shelf 312 areobjects to be displayed through glass front 314. Light modules 306 aremounted on frame 304 so as to illuminate objects 310 favorably. There isa good deal of flexibility in the positioning of modules 306. Asdiscussed with reference to FIG. 5, the modules may be mounted invarious positions in both the x- and y-directions of the horizontalshelf. As described with reference to FIG. 4, reflectors 308 areadjustably mounted on modules 306 such that light beams 316 may bedirected to illuminate objects 310 at a desired angle, and variouscharacteristics of the emitted light may be obtained by the choice oflenses (if any) used on reflectors 308. An additional lighting system303 may be mounted on the underside of shelf 312 if objects placed onshelf 316 are desired to be illuminated.

Returning to FIG. 5, frame 100 may be employed as a multipletrack-lighting fixture mounted on a ceiling or wall. Frame 100,preferably with a diffusive and protective cover, may be used as aceiling light fixture. In rooms with suspended ceilings, frame 100 maybe adapted to fit into the ceiling grid in place of a ceiling panel.Moreover, several frames 100, of the same or different sizes, may beused together as building blocks or components to construct a two- orthree-dimensional lighting system, e.g., a two-dimensional system in theshape of the letter “E,” or a three-dimensional system in the shape of acube or parallelepiped, or combinations of same, with light modulesmounted on some or all faces.

A frame need not be rectangular. FIG. 6 shows an elevational view of acircular frame 120 based on the same wiring and insulating principles asframe 100. In FIG. 6, each electrically conductive channel isrepresented by a single line, rather than a double line as in FIG. 5, toillustrate the electrical circuit more clearly. The drawing shows threepairs of channels, 122 and 124, 126 and 128, and 130 and 132, that areessentially arranged on concentric circles on dielectric surface 134 offrame 120. When terminals 134 and 136 are energized with suitableelectrical power, one or more light modules may be operatively mountedon one or more channel pairs. In a variation of the embodiment of FIG.6, a single pair of channels is arranged in a spiral on the circularframe rather than in a pattern of concentric circles. It is within thescope of the invention to modify frame 120 and the channels on itssurface by stretching their circular shapes into various other shapes,such as an oval, crescent, etc.

Aspects of the invention are applicable also to three dimensions. FIG.7A depicts an elevational view of spherical frame 140 based on the samewiring and insulating principles as frame 100 of FIG. 5. As in FIG. 6,the electrically conductive channels in FIG. 7A are shown as singlelines. Channel pair 142 comprises channels 142A and 142B; likewise,channel pairs 144, 146, 148, and 150 are each comprised of two channels.In this embodiment, the electrical circuit is located entirely on thedielectric surface 141 of sphere 140. Channel pairs 142, 144, 146, 148,and 150 are substantially latitudinal circles of sphere 141. The circuitmay be energized by connecting terminals 152 and 154 to a suitable powersource.

In order to mount light modules on spherical frame 140, the framesurface must be substantially flat. The term “substantially flat” asused herein with respect to a frame surface means that the frame surfaceeither is flat or has a radius of curvature large enough to permit lightmodules to be mounted on the frame surface by magnetic attractionwithout slippage or rocking. The distance between channels of eachchannel pair should be small enough so that reliable electrical andthermal contact occurs between the channels and corresponding paths of amounted light module. To facilitate reliable electrical and thermalcontact between frame channels and the corresponding paths of a mountedlight module, the surface of the light module may be curved to match oraccommodate the curvature of the frame. The term “substantially flat” asused herein with respect to a module surface means that the modulesurface may be either flat or curved such that the module may be mountedon the frame surface by magnetic attraction without slippage or rocking,although the curvatures of the frame and module surfaces need not beidentical. Further, the frame channels may be raised from the surface ofthe frame, as shown in FIG. 2, and/or the module's paths may be raisedfrom the body of the module. Additionally, the module may include springcontacts, typically formed from beryllium copper, that may be shaped toconform to the curvature of the frame. Spring contacts will enhance heattransfer away from the module and improve module stability particularlywhere the path/channel contacts between the module and frame are narrow.By using a judicious combination of the aforementioned techniques, alight module may be designed such that it can be magnetically mountedsecurely on a frame even when the surface of the frame is curved.

While FIG. 7A depicts a spherical frame, the same principles apply to acylindrical or conical frame and other curved three-dimensional frames.Particularly in three dimensional embodiments of the invention, it maybe advantageous to conserve weight by employing a frame comprisingnon-magnetic material, such as plastic, with pieces of magnetic materialimbedded in the frame or adhered on the inside of the frame. In suchembodiments, however, the mass of the imbedded magnetic material must belarge enough to satisfy the heat-sinking function and, as is the case inall embodiments of the invention utilizing the heat-sinking ability ofthe magnetic materials, the size of the contact areas between the frameand module must be sufficient to permit adequate heat transfer from themodule to the frame.

FIG. 7B shows the same spherical frame 140 except that the channel pairs142, 144, 146, 148, and 150 are full latitudinal circles on dielectricsurface 141 of sphere 140. In this embodiment, terminals 152 and 154protrude into the interior of frame 140. Looking through the break-awayin the drawing, terminal 152 is electrically connected to the firstchannel of each channel pair as illustrated by connecting wires 156,158, and 160. Terminal 154 is electrically connected to the secondchannel of each channel pair as illustrated by connecting wires 162,164, and 166. Additional connecting wires to the remaining channels areomitted in FIG. 7B for clarity. It is within the scope of the inventionto modify frame 140 by stretching it into various other shapes, such asan ellipsoid, etc. In a variation of the embodiment of FIG. 7A, a singlepair of channels forms a spiral over the surface of sphere 141, runningessentially from the north pole to the south pole. The embodiments ofFIGS. 7A and 7B are typically used in lighting systems hung from aceiling or mounted on a pole-type base. For a lighting system mounteddirectly on a horizontal or vertical surface, half of frame 140, i.e., ahemisphere, may be employed using the same principles illustrated inFIGS. 7A and 7B.

FIG. 7B illustrates the concept that electrical power may be supplied tothe frame channels from inside the frame of the lighting system. Variouselectrical control devices, such as ballasts, dimmers, transformers,power supplies, inverters, drivers, controllers, etc., may also belocated within the body of the frame such that the lighting system maybe connected directly to a standard power source, say, 110 volts,alternating current. Moreover, such control devices may each service oneor more light modules, such as one ballast servicing four or eightfluorescent light modules. This feature of the invention may be employedwith three-dimensional frames, e.g., a cube, sphere, or polyhedron, andit may also be utilized with two-dimensional frames, such as thosedepicted in FIGS. 1, 5, and 6, by extending the electrical channels tothe inside of the frame bodies rather than directly to externalterminals as shown in the drawings.

In further aspects of the invention, FIGS. 8A and 9A illustrateadditional examples of embodiments of three-dimensional frames. FIG. 8Aillustrates an icosahedron frame 180 having twenty equal faces 182, eachface being an equilateral triangle as shown in FIG. 8B. Terminal 181,comprising dual electrically isolated wires, extends inside the body offrame 180 and provides means for supplying electrical power to lightmodules from within frame 180. FIG. 9A illustrates a dodecahedron frame190 having twelve equal faces 192, each face being an equilateralpentagon as shown in FIG. 9B. Terminal 191, comprising dual electricallyisolated wires, extends inside the body of frame 190 and provides meansfor supplying electrical power to light modules from within frame 190.As shown in the drawings, electrically conductive channels 184 and 186may be centrally located on dielectric-coated triangular face 182, andlikewise for electrically conductive channels 194 and 196 ondielectric-coated pentagonal face 192, although the orientation of thesechannels within the triangular or pentagonal faces is not critical.Faces 182 and 192 comprise magnetic material so that a light module maybe mounted on each face. Channels 184 and 186 are electrically isolatedfrom each other and from face 182, and likewise for channels 194 and 196from face 192. Channels 184 and 186 pass through face 182 and areconnected to terminal 181 such that electrical power may be suppliedfrom inside the body of icosahedron frame 180 in the same way as shownin FIG. 7B, and likewise for channels 194 and 196 from insidedodecahedron frame 190.

Additional solid shapes for frames in accordance with various aspects ofthe invention, such as cylinders, cones, prisms, combinations andfrustums of various solids, etc., may be constructed by one with skillin the art using the same principles as described above. Theseadditional embodiments are within the scope of the invention.

As described in the foregoing examples, numerous embodiments andvariations of the frame structure are possible and practical. In all ofthese embodiments, it is important that the electrical paths of thelight module be properly positioned on the electrical channels of theframe so that the light module can be reliably powered. Pictorials orgraphics may be employed to provide guidance as to the properorientation of modules on the frame. FIG. 10 shows the lighting systemof FIG. 2 with the addition of ridges 206, 208, and 210 and receivinggroove 212. Assuming, for the moment, that ridge 210 and groove 212 areomitted, ridges 206 and 208 insure that light module 200 is properlyaligned electrically when mounted on frame 204 except, possibly, forelectrical polarity. With ridge 210 positioned within groove 212, properpolarity is assured because the ridge and groove, both located to theright of center-line B-B in the drawing, are not centered on frame 204.Note, ridge 210 and groove 212 may not always be necessary or desiredas, for example, where the light module 200 is powered by alternatingcurrent.

In a direct-current embodiment where light source 214 is an LED andridge 210 and groove 212 have been omitted, a user would realize thatthe light module was mounted with improper polarity by virtue of thefact that the LED did not light when energized, whereupon the user wouldremount the light module with the polarity reversed. Alternatively, thelight module may include two LEDs, each lighting with opposite polarity,so whatever the polarity of the module one LED would light. A lightmodule with two LEDs of opposite polarity will function with alternatingcurrent. Another dual-LED alternative is where each LED emits differentcolored light, say, the first LED emitting white light and the second,with opposite polarity, emitting red light. Emitted red light mightsignal the user that the light module is mounted with the wrongpolarity, or it may be a design feature of the light module that it canemit different colored light depending on its polarity position on theframe or depending on the polarity supplied to the lighting system. Thelatter case may be employed in a signaling system, because the color ofthe emitted light, e.g., red or green, could be changed by reversing thepolarity supplied to the lighting system. Additional signaling options,such as blinking, could be achieved by pulsing the power supplied to thelighting system. A single light module may be comprised of two groups ofLEDs with one group responding to a first applied polarity and thesecond group responding to the opposite applied polarity or,alternatively, a lighting system may employ two groups of light modules,one group of modules responding to a first polarity and the second groupof modules responding to the opposite applied polarity.

FIG. 11 shows the lighting system of FIG. 3 with the addition of ridge222 on frame 226 and matching groove 224 in light module 228. Ridge 222is asymmetrical, having one vertical side (left side in the drawing) andone slanted side (right side in the drawing), and likewise for matchinggroove 224. Mounting module 228 on frame 226 with ridge 222 properlypositioned within groove 224 insures reliable electrical contacts andproper polarity, irrespective of whether or not groove is centered withrespect to center-line C-C. There are numerous other possiblearrangements of ridges, grooves, and/or other means in accordance withvarious aspects of the invention for insuring the light module will bemounted on the frame with reliable electrical contacts between themodule and frame and, where appropriate, proper electrical polarity.

In each of the foregoing embodiments of the invention, there is thecapability for a variable number of light modules to be electricallyconnected in parallel on a frame connected to an external power supplyor driver circuit. Because the light modules may be added or removedfrom the frame at any time, the power supply must be capable ofregulating the supply current such that an appropriate current will beprovided to each light module. Such regulated power supplies are knownin the art. See, for example, U.S. Pat. No. 6,577,512, issued Jun. 10,2003, to Tripathi et al., which describes a power supply for a variablenumber of LEDs wired in series or in parallel.

In an embodiment employing a variable number of LED light modulesconnected in parallel, the driver circuit may need the ability to detectthe number of light modules mounted on the frame in real time. Aresistor added in parallel with the LED on each module will facilitatethe driver circuit's ability to detect the number of LED light modulesmounted at any time. By periodically detecting the equivalent resistanceof the mounted LED modules, the driver circuit would regulate the supplycurrent accordingly.

Referring again to the above-mentioned Wulfman et al. patent, thepresent invention may be employed in low- or high-voltage applicationswith LED, incandescent, quartz-halogen, or fluorescent light sources,whereas Wulfman et al. teaches only a low-voltage quartz-halogen system.A frame of the present invention may be adapted to support light modulesin one, two, or three dimensions, whereas the Wulfman et al. housingsare constrained to a linear track. An advantage of the present inventionnot taught by Wulfman et al. is the feature that the magnetic materialsin the frame and light module serve the dual purpose of mounting andheat-sinking in LED embodiments. In applications where it is desirableto have the lighting system be as inconspicuous as possible such as anunder-counter system for lighting merchandise, the bracket and fixturesof Wulfman et al. will occupy significantly more space and be moreconspicuous than a lighting system in accordance with the invention,particularly in an embodiment employing LED light sources. There arefurther advantages. The present invention may be employed in signage orsignaling applications. Lighting systems in accordance with the presentinvention may be used as components or building blocks in largerlighting systems. Lighting systems in accordance with the presentinvention may be fabricated with three-dimensional frames that have anaesthetic appearance even when the lighting system is not illuminated.The present invention has a far wider variety of applications than thelighting system of Wulfman et al. and provides a user with enhancedability to control the quantity, direction, and characteristics of theemitted light.

While there have been shown what are at present considered to be thepreferred embodiments of the invention, it will be apparent to thoseskilled in the art that various changes and modifications can be madeherein without departing from the scope of the invention as defined inthe appended claims. Accordingly, it should be understood that theinvention has been described by way of illustration and not limitation.

1. A lighting system with removable light modules comprising: (a) a frame having a substantially flat surface, said frame including a magnetic material and first and second electrically conductive channels mounted on said surface such that said channels are electrically isolated from each other; (b) a light module comprising an LED light source having sufficient lumen output for use in general lighting applications mounted on a base, said base having a top surface and a substantially flat bottom surface with a dielectric coating covering said top and bottom surfaces and a magnetic material between said top and bottom surfaces, first and second electrically conductive paths mounted on said top dielectric surface such that said paths are electrically isolated from each other, said LED light source having first and second electrically conductive lead-in wires electrically connected to said first and second paths, respectively, and said magnetic material of said base and said magnetic material of such frame providing adequate heat-sink means for the thermal operating requirements of said LED light source; and (c) said light module being mounted on said frame with said substantially flat bottom surface of said light module facing said substantially flat surface of said frame, said first path of said light module being in electrical contact with said first channel of said frame and electrically isolated from said second channel, said second path of said light module being in electrical contact with said second channel of said frame and electrically isolated from said first channel, said light module being securely mounted on said frame by means of a magnetic attractive force acting between said magnetic material of said light module and said magnetic material of said frame and such that said magnetic attractive force permits said light module to be manually removed from said frame.
 2. A lighting system as described in claim 1 wherein said first and second electrically conductive paths of said light module are thin electrically conductive strips.
 3. A lighting system as described in claim 1 wherein said substantially flat surface of said frame has a dielectric coating thereon and said first and second channels are mounted on said dielectric coating of said frame.
 4. A lighting system as described in claim 1 wherein said frame includes means for insuring proper electrical polarity between said first and second electrically conductive channels of said frame and said first and second electrically conductive paths of said base of said light module.
 5. A lighting system as described in claim 1 wherein said lighting system includes a plurality of light modules mounted on said frame.
 6. A lighting system as described in claim 1 wherein said lighting system includes a plurality of electrically conductive channel pairs.
 7. A lighting system as described in claim 1 wherein said frame has a substantially three-dimensional shape.
 8. A lighting system as described in claim 1 wherein said light module emits colored light.
 9. A lighting system as described in claim 1 wherein said lighting system includes an electrical control device servicing said module, said electrical control device being located within the body of said frame.
 10. A lighting system as described in claim 1 wherein said lighting system includes first and second LEDs and the polarity of the first LED is opposite to that of the second LED.
 11. A lighting system with removable light modules comprising: (a) a frame having a substantially flat surface, said frame including a magnetic material and first and second electrically conductive channels mounted on said surface; (b) a light module comprising a light source mounted on a base, said base having a substantially flat surface, said base including a magnetic material and first and second electrically conductive paths, said light source having first and second lead-in wires electrically connected to said first and second electrically conductive paths of said base; (c) said light module being mounted on said frame with said substantially flat surface of said light module facing said substantially flat surface of said frame and said first path of said light module being in electrical contact with said first channel of said first frame and electrically isolated from said second channel and said second path of said light module being in electrical contact with said second channel of said second frame and electrically isolated from said first channel such that said light module is securely mounted on said frame by means of a magnetic attractive force acting between said magnetic material of said light module and said magnetic material of said frame and such that said magnetic attractive force permits said light module to be manually removed from said frame; and a housing enclosing said frame and said light module, said housing including an openable light-transmissive cover that when closed prevents access to said first and second electrically conductive channels and a kill switch responsive to the position of said cover such that the electrical power flowing through said channels is shut off when said cover is open.
 12. A lighting system as described in claim 11 wherein said light source is a fluorescent lamp. 